Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/unittest_custom_options.proto

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
@@ skipping 11 matching lines @@
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Author: benjy@google.com (Benjy Weinberger)
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 //
-// A proto file used to test the "custom options" feature of proto2.
+// A proto file used to test the "custom options" feature of google.protobuf.
 
+syntax = "proto2";
 
 // Some generic_services option(s) added automatically.
 // See:  http://go/proto2-generic-services-default
 option cc_generic_services = true;     // auto-added
 option java_generic_services = true;   // auto-added
 option py_generic_services = true;
 
 // A custom file option (defined below).
 option (file_opt1) = 9876543210;
 
@@ skipping 164 matching lines @@
   option  (double_opt) = -154;
 }
 
 // Options of complex message types, themselves combined and extended in
 // various ways.
 
 message ComplexOptionType1 {
   optional int32 foo = 1;
   optional int32 foo2 = 2;
   optional int32 foo3 = 3;
+  repeated int32 foo4 = 4;
 
   extensions 100 to max;
 }
 
 message ComplexOptionType2 {
   optional ComplexOptionType1 bar = 1;
   optional int32 baz = 2;
 
   message ComplexOptionType4 {
     optional int32 waldo = 1;
 
     extend google.protobuf.MessageOptions {
       optional ComplexOptionType4 complex_opt4 = 7633546;
     }
   }
 
   optional ComplexOptionType4 fred = 3;
+  repeated ComplexOptionType4 barney = 4;
 
   extensions 100 to max;
 }
 
 message ComplexOptionType3 {
   optional int32 qux = 1;
 
   optional group ComplexOptionType5 = 2 {
     optional int32 plugh = 3;
   }
@@ skipping 16 matching lines @@
   optional group ComplexOpt6 = 7595468 {
     optional int32 xyzzy = 7593951;
   }
 }
 
 // Note that we try various different ways of naming the same extension.
 message VariousComplexOptions {
   option (.protobuf_unittest.complex_opt1).foo = 42;
   option (protobuf_unittest.complex_opt1).(.protobuf_unittest.quux) = 324;
   option (.protobuf_unittest.complex_opt1).(protobuf_unittest.corge).qux = 876;
+  option (protobuf_unittest.complex_opt1).foo4 = 99;
+  option (protobuf_unittest.complex_opt1).foo4 = 88;
   option (complex_opt2).baz = 987;
   option (complex_opt2).(grault) = 654;
   option (complex_opt2).bar.foo = 743;
   option (complex_opt2).bar.(quux) = 1999;
   option (complex_opt2).bar.(protobuf_unittest.corge).qux = 2008;
   option (complex_opt2).(garply).foo = 741;
   option (complex_opt2).(garply).(.protobuf_unittest.quux) = 1998;
   option (complex_opt2).(protobuf_unittest.garply).(corge).qux = 2121;
   option (ComplexOptionType2.ComplexOptionType4.complex_opt4).waldo = 1971;
   option (complex_opt2).fred.waldo = 321;
+  option (complex_opt2).barney = { waldo: 101 };
+  option (complex_opt2).barney = { waldo: 212 };
   option (protobuf_unittest.complex_opt3).qux = 9;
   option (complex_opt3).complexoptiontype5.plugh = 22;
   option (complexopt6).xyzzy = 24;
 }
 
 // ------------------------------------------------------
 // Definitions for testing aggregate option parsing.
 // See descriptor_unittest.cc.
 
 message AggregateMessageSet {
@@ skipping 84 matching lines @@
     optional int32 nested_field = 1 [(field_opt1) = 1002];
   }
   enum NestedEnum {
     option (enum_opt1) = 1003;
     NESTED_ENUM_VALUE = 1 [(enum_value_opt1) = 1004];
   }
   extend google.protobuf.FileOptions {
     optional int32 nested_extension = 7912573 [(field_opt2) = 1005];
   }
 }
+
+// Custom message option that has a required enum field.
+// WARNING: this is strongly discouraged!
+message OldOptionType {
+  enum TestEnum {
+    OLD_VALUE = 0;
+  }
+  required TestEnum value = 1;
+}
+
+// Updated version of the custom option above.
+message NewOptionType {
+  enum TestEnum {
+    OLD_VALUE = 0;
+    NEW_VALUE = 1;
+  }
+  required TestEnum value = 1;
+}
+
+extend google.protobuf.MessageOptions {
+  optional OldOptionType required_enum_opt = 106161807;
+}
+
+// Test message using the "required_enum_opt" option defined above.
+message TestMessageWithRequiredEnumOption {
+  option (required_enum_opt) = { value: OLD_VALUE };
+}